Fearing to state the obvious, Britten's Peter Grimes is more than the sum of its parts. Given that in this case there are many parts – large orchestra, onstage band, offstage tuba and organ, actors, children, expanded chorus and a dozen named roles all requiring vivid characterisation – I hope such an apparently bland observation about one of the masterpieces of the 20th century can be allowed.

This simple truth struck home this week after the Royal Opera's first revival of Willy Decker's 2004 staging, created at La Monnaie, Brussels a decade earlier and still ferocious in impact despite some uneven performances and a technical hitch or two. Almost abstract in John Macfarlane's harsh, dark designs, a mix of expressionist angst and mid-Victorian naturalism, Decker's production wrenches the work from its East Anglian locale – no lobster pots or cod-bangers here – to celebrate its universality.

At the same time the Borough, that tight-knit community of village gossips who swarm and sting together, display an uptight, two-faced moral turpitude which is all too recognisable – dare one say recognisably English? – and the great lowering sky, as black-smudged as one of Constable's wild cloud studies, keeps Suffolk scorched in our imagination.

You might complain that the grisly characters Britten and his librettist Montagu Slater assembled (after George Crabbe's poem The Borough) are rendered indistinguishable in their sub-fusc frockcoats and fussy bonnets, a stark contrast to ENO's equally radical recent staging by David Alden in which all were decked out with colourful, idiosyncratic variety as if styled by Georg Grosz.

Yet here, with gifted actor-singers such as Matthew Best (Swallow), Roderick Williams (Ned Keene), Jonathan Summers (Balstrode) and Alan Oke (Bob Boles), identification presented no problem. We knew each one of them. Jane Henschel's Mrs Sedley, Catherine Wyn-Rogers's Auntie and her "nieces", the lively duo of Rebecca Bottone and Jette Parker young artist Anna Devin, conveyed both their individuality and their numbing, circumscribed ordinariness.

Whether united in terrifying choral unison or alone as cameos, the Borough plays a bigger role than Grimes himself. Which is why the distressing vocal struggles of Ben Heppner, reprising the title role, could not diminish the achievement of the whole. His hulking, lonely presence as the violent fisherman stirred powerful emotion, underlining his fateful vulnerability if not quite in the way Britten intended. Only at moments did we glimpse that pure, floating tenor line which has long been a Heppner trump. At times he wandered into strange, distant keys.

Nonetheless when he lifted his boy apprentice (Patrick Curtis) with bullying ease as if he were a bag of feathers, Heppner conjured all the tragedy and monstrousness of a great, archetypal Grimes. I had bitten a hole in my cheek by the end. Amanda Roocroft, a sympathetic Ellen Orford, also had first-night vocal lapses but who knows what tensions they were all suffering: a press announcement later stated that because of a broken motor to move the massive back wall, the staging had to be altered mid-performance to ensure the show could continue. You would never have known. The conductor Andrew Davis, at home in this repertoire, and the Royal Opera orchestra captured the salt spray and seagull cries which haunt every detail of this score, while never losing sight of the overarching horizon. Don't be deterred by glitches: this is unmissable.

As a footnote, before writing this column I asked the composer Robert Saxton, as a boy an occasional and informal pupil of Britten's, why he thought Peter Grimes such a singular achievement. With each new encounter, it feels like one of the finest operas ever written. He answered with an illuminating anecdote. Perhaps it is well known. If not, it seems worth putting on record: during the second world war when Britten was writing Grimes (1945), he sometimes stayed in Suffolk with his sister, Beth Welford (1909-1989), and her young family.

Saxton, as he remembers it, bumped into Beth in Aldeburgh High Street near the end of her life. She regaled him with tales of how her younger brother was always desperate to drive to Ipswich library to check out scores by operatic masters such as Verdi to solve some of his own technical problems. But this was a time of air raids and petrol rationing. Beth, in effect, told him not to be so silly and to stay right where he was. "And that," she told Saxton, to paraphrase, "is one reason why Peter Grimes is unlike anything else. Ben had to rely on what was in his head."

Luke Bedford (b 1978), who like Britten studied at the Royal College of Music, but not confined by bombs or rationing, turned towards the European avant garde for inspiration, has won several prizes and is in the forefront of a generation of composers who can still be called young. His first opera, Seven Angels, to a text by Glyn Maxwell, is a serious affair. Milton's Paradise Lost, the work's starting point, is hardly a chuckler, but it has its ironic moments as well as bristling with dense high drama. The Fall of Man takes only 10 words – "Greedily she gorged without restraint/ And knew not eating death" – which is way shorter than a tweet.

A dose of similar rigour could have enlivened Seven Angels. In two acts and lasting 90 minutes, this cantata-like piece is full of glistening but slow-moving music beautifully rendered by its commissioners, Birmingham Contemporary Music Group and the Opera Group. The conductor Nicholas Collon had prepared his musicians faultlessly. Director John Fulljames and Japanese designer Tadasu Takamine – who currently has an exhibition at the city's Ikon gallery – have created a streamlined show with a pop-up book as a central metaphor.

But the agitprop is heavy-handed, the action almost nonexistent, despite urgent efforts on the part of the expert cast who declaim their lines with patient dedication. Seven nameless angels fall out of the sky to "an ashen plain". Through a series of symbolic stories involving unnamed types – a king, a prince, an industrialist – they piece together the knowledge of a once abundant garden laid waste by human folly. Friends of the Earth are credited among the supporters and apparently a keen member made his own impromptu plea, which I missed, from the platform at the end.

In a week of music entirely by British composers, the culmination was a performance of Byrd's monumental Great Service, sung by the Gabrieli Consort and conducted by their director Paul McCreesh, as part of this year's Spitalfields festival. Relayed live on Radio 3 and definitely worthy of a listen again before time runs out tomorrow, it was spellbinding. An ensemble of superb unaccompanied voices soared in elaborate polyphony, interspersing the Byrd with contemporary motets by Gabriel Jackson (b 1962) and Jonathan Dove (b 1959).

Dove's two world premieres will surely become repertoire fixtures. The tender "Care Charmer Sleep" rose through a sequence of ascending arpeggios to ecstatic fortissimos before a hushed conclusion. Church music is one of the few areas where contemporary composers are given an enthusiastic hearing, often performed by nonspecialists. If God does not exist, it would be worth not letting on for music's sake.

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